PURPOSE: To obtain a compound useful as an amino acid soap having also beautifying and whitening action in good yield at a low cost in simple operation by reacting cysteines with an alkanoyl chloride.
CONSTITUTION: A cysteine expressed by formula I (R1 is H, methyl or ethyl) or a derivative thereof is reacted with an alkanoyl chloride expressed by the formula R2COCl (R2 is 8-22C alkyl) using a ketonic solvent, such as acetone, under alkaline conditions by regulating pH of the reaction solution to 7-9 and cooling the solution at ambient temperature or below to afford the objective substance expressed by formula II. The solvent is preferably used in an amount so as to homogenize the reaction system containing the alkanoyl chloride and aqueous solution of an alkali added thereto, i.e. within the range of (1:1)-(1:0.5) ratio of ketone : water. Only the amino group is alkanoylated without reacting sulfide group at all by using the ketonic solvent.
TSUCHIDA OSAMU
FUKUDA KAZUHIKO
Next Patent: SYNTHESIS OF BETA-LACTAM USING METAL COMPOUND AS CATALYST